This relates generally to testing electronic devices and more particularly, to testing electronic devices that include multiple antennas.
Electronic devices often incorporate wireless communications circuitry. For example, devices may communicate using the Wi-Fi® (IEEE 802.11) bands at 2.4 GHz and 5.0 GHz. Wireless communications are also possible in cellular telephone telecommunications bands and other radio-frequency bands. In schemes such as antenna diversity schemes, an electronic device may use an array of multiple antennas to handle wireless communications.
When manufacturing such types of multi-antenna wireless devices in large volumes, the performance of the wireless communications circuitry on each device can be evaluated using a radio-frequency test station to ensure that each device satisfies design criteria. A radio-frequency test station typically includes a test host a tester (i.e., a signal generator), and an electromagnetic shielding test enclosure having a test antenna. The signal generator is connected to the test host. Arranged in this way, the test host directs the signal generator to transmit radio-frequency signals via the test antenna in the electromagnetic shielding test enclosure to a corresponding electronic device under test (DUT) during production testing.
In conventional radio-frequency test arrangements, a wireless DUT having only one antenna is placed into the electromagnetic shielding test enclosure. The test host directs the signal generator to broadcast downlink test signals to the DUT (i.e., the signal generator radiates test signals to the DUT using the test antenna in the shielding test enclosure). The DUT receives the downlink test signals using its antenna.
The DUT may be configured to analyze the received downlink test signals and to determine whether its wireless communications circuitry satisfies performance criteria. For example, the DUT can compute a receive power level based on the received downlink signals. If the receive power level is less than a predetermined threshold, the DUT is marked as a passing DUT. If the receive power level is greater than the predetermined threshold, the DUT is marked as a failing DUT.
Testing a multi-antenna device in this way may not be suitable for testing DUTs containing at least first and second antennas and may yield inaccurate results because the conventional test method holds the DUT in a fixed position within the electromagnetic shielding test enclosure. If in the fixed position the placement of the first antenna is closer to the test antenna, measurement results may be skewed towards the first antenna (i.e., test results may be more accurate for the first antenna and less accurate for the second antenna). If in the fixed position the place of the second antenna is closer to the test antenna, measurement results may be skewed towards the second antenna (i.e., test results may be more accurate for the second antenna and less accurate for the first antenna). There are also cases where the at least two antennas are both the same distance from the test antenna but the device's orientation favors one antenna compared to another due to polarization or the near or far-field pattern of the device.
It may therefore be desirable to provide improved ways for testing electronic devices having multiple antennas in a production environment.